This invention relates in general to packages for holding semiconductor chips and in particular to a reusable package for holding a semiconductor chip.
Certain types of packages for holding semiconductor chips are very expensive. Thus a ceramic pin grid array type package may cost $50-$70 per package. When the chip package is no longer usable, the package together with the chip are frequently simply discarded. Disposal of expensive packages in such manner is wasteful of resources. However, conventional packages are not easily reclaimed as explained below.
A conventional ceramic package typically has a cavity for holding the chip. A die attach pad is attached to the bottom surface of the cavity. The die is then attached to the top surface of the die attach pad. Selective points on the die are then connected by bonding wires and bonding fingers to outside pins. The cavity is then sealed by a lid. In order to reclaim the package after it has been used for a chip, the lid is first removed and the original semiconductor die and perhaps also the die attach pad must also be removed before the package can be reused for a different die.
When the original die and the die attach pad are first attached to the bottom surface of the cavity of the package, they are attached securely to assure best performance of the packaged chip during its useful life. For this reason, after the die and the die attach pad are attached to the bottom surface of the cavity, it is difficult to remove the die and the die attach pad from the package. Hence, the cost of reclaiming the package may be comparable to the cost of a new package. This renders reclamation of used expensive packages such as the ceramic pin grid array type packages unattractive.
It is therefore desirable to provide a different type of package which is easier and less expensive to reclaim.